Psychophysics of Reading - Normal and Low Vision Abstract Reading difficulty is one of the most disabling consequences of vision loss for five million Americans with low vision. Difficulty in accessing print imposes obstacles to education, employment, social interaction and recreation. The ongoing transition to the production and distribution of digital documents brings about new opportunities for people with visual impairment. Digital documents on computers and mobile devices permit easy manipulation of print size, contrast polarity, font, page layout and other attributes of text. In short, we now hae unprecedented opportunities to adapt text format to meet the needs of visually impaired readers. In recent years, our laboratory and others in the vision-science community have made major strides in understanding the impact of different forms of low vision on reading, and the dependence of reading performance on key text properties such as character size and contrast. But innovations in reading technology have outstripped our knowledge about low-vision reading. A major gap still exists in translating these laboratory findings into methods for customizing text displays for people with low vision. The broad aim of the current proposal is to apply our knowledge about the impact of vision impairment on reading to provide tools and methods for enhancing reading accessibility in the modern world of digital reading technology. Our research plan has three specific goals: 1) To develop and validate an electronic version of the MNREAD test of reading vision, to extend this technology to important text variables in addition to print size, and to develop methods for customizing the selection of text properties for low-vision readers. MNREAD is the most widely used test of reading in vision research and was originally developed in our laboratory with NIH support. 2) To investigate the ecology of low-vision reading in order to better understand how modern technologies, such as iPad and Kindle are being used by people with low vision. We plan to evaluate the feasibility of using internet methods to survey low-vision individuals concerning their reading behavior and goals, and of collecting approximate measures of visual function over the internet. We also plan to develop an accessibility checker to help low-vision computer users and their families to evaluate the accessibility of specific text displays. 3) To enhance reading accessibility by developing methods for enlarging the visual span (the number of adjacent letters that can be recognized without moving the eyes). A reduced visual span is thought to be a major factor limiting reading in low vision, especially for people with central-field loss from macular degeneration. We have already demonstrated methods for enlarging the visual span in peripheral vision. We plan to develop a more effective perceptual training method for enlarging the visual span, with the goal of improving reading performance for people with central-vision loss.